Structure and function of human sweat glands studied with histochemistry and cytochemistry (2023)

Textile biosensors are emerging in non-invasive health monitoring for analysis of human biofluids such as sweat. In order to measure the concentration of metabolites, electrolytes and trace metals of human sweat for the diagnosis of people's physiological conditions in real time, smart textile-based biosensors can be incorporated into wearable clothing (e.g. clothing). In this review, recent innovations and applications of sweat-sensing textile-based biosensors, including material formulation, electrode fabrication, and fabrication techniques, were discussed. The use of various advanced nanocomposite materials such as metal, carbon and conductive polymers in textile-based sweat detection biosensors was synthesized. An in-depth discussion of electrochemical detection technologies such as amperometric, potentiometric, square wave voltammetry, and conductometric methods was provided. Several types of manufacturing technologies have been discussed for incorporating advanced nanocomposite materials into textile substrates, including dip coating, inkjet printing, and screen printing. Furthermore, enzymatic and non-enzymatic processes have been mentioned to optimize the performance of textile biosensors. Finally, the main challenges that limit the practical applications of smart textile biosensors for sweat detection were evaluated, along with the prospects for conveniently monitoring human health. A collaboration between engineers, biologists and clinicians is recommended to utilize the full potential of smart textile biosensors that use human sweat in monitoring healthcare around the world.

For patients with extensive skin defects, the loss of sweat glands (SwGs) greatly diminishes their quality of life. In fact, difficulties in thermoregulation, ion reabsorption and maintenance of water balance can make them susceptible to hyperthermia, heatstroke or even death. Despite extensive studies on the biology of skin stem cells in recent years, the in situ regeneration of SwGs with structural and functional fidelity is still a challenge due to the limited regenerative capacity and control of the cell fate of the resident progenitors. To overcome these challenges, one needs to consider intrinsic factors relevant to genetic and epigenetic regulation and cues from the cellular microenvironment. Here, we describe recent progress in molecular biology, developmental pathways, and cell evolution associated with SwG development and maturation. This is followed by a summary of current strategies used for cell fate modulation, transmembrane drug delivery, and scaffold design associated with SwGre generation. Finally, we offer perspectives for creating more sophisticated systems to accelerate patients' innate healing capacity and develop skin constructs designed to treat or replace structurally and functionally damaged tissue.

Journal of Dermatological Science, Volume 72, Issue 2, 2013, pp. 177-182

Analytical Chemistry Acta, Volume 812, 2014, pp. 228-235

A fluorescent nanocomposite based on the inclusion of CdSe quantum dots in porous phosphate heterostructures, functionalized with amino groups (PPH-NH₂@CdSe), was synthesized, characterized and used for fingerprint detection. The main scopes of this work were: first to develop a friendly chemical powder for detecting latent fingerprints, especially on non-porous surfaces; their posterior intercalation in the PPH structure allows not to scatter the fluorescent nanoparticles, so very good fluorescent images can be obtained. Fingerprints, obtained from different non-porous surfaces such as iron tweezers, cell phone screens and credit card magnetic strips, treated with this powder emit a pale orange luminescence under ultraviolet excitation. Another image processing is contrast enhancement which allows obtaining positive matches according to the information provided by a police database and proved to be more effective than that obtained with unprocessed images. The experimental results illustrate the effectiveness of the proposed methods.

The Journal of Steroid Biochemistry and Molecular Biology, Volume 217, 2022, Artigo 106026

The scent (musk) gland is an organ unique to muskrats and other odor-secreting animals, and the pheromones (musk) synthesized and secreted by the scent gland play a role in chemical communication between odor-secreting animals. The musk gland is synchronized with changes in testicular development; however, little is known about testicular androgen secretion and how it regulates pheromone synthesis and odor secretion. To investigate the effect of androgens on pheromone synthesis in the musk gland, we established a muskrat castration model by surgical removal of the testis and analyzed the histomorphology, hormone concentration, gene expression, and changes in the chemical composition of the musk gland. in castration and control groups by histomorphological analysis, enzyme-linked immunosorbent assay (ELISA), RNA sequencing (RNA-seq) and gas chromatography mass spectrometry (GCIN). The results of the histomorphological analysis showed that, after castration, muskrat gland cells underwent significant atrophy.P< 0.05). The results of the hormone measurement showed that there was a significant decrease in serum testosterone and musk rat testosterone (P< 0.05) after muskrat castration. Transcriptome sequencing results showed that 510 differentially expressed transcripts (DETs) were enriched mainly in fatty acid metabolism, terpenoid backbone biosynthesis, fatty acid degradation, PPAR signaling pathway and fatty acid biosynthesis. CGMS results showed that macrocyclic ketones, steroids, fatty acids, alcohols and esters in musk were significantly altered (P< 0.05). In conclusion, it was found that androgens play an important role in the chemical communication exchange between muskrats through the regulation of pheromone synthesis in musk cells. This study provides a basis for understanding the mechanism of androgen-influenced animal communication.

European Journal of Cell Biology, Volume 95, Edição 8, 2016, pp. 252-264

Caveolins (Cav-1, -2 and -3) and Cavins (Cavin-1, -2, -3 and -4) are two families of proteins that control the biogenesis and function of caveolae, omega-like invaginations of the plasma membrane representing the primary site of important cellular processes such as endocytosis, cholesterol homeostasis and signal transduction. Caveolae are especially abundant in adipose tissue, playing a consistent role in several processes such as insulin-dependent glucose uptake and transmembrane transport of lipids underlying adipocyte differentiation, maintenance, and adaptive hypertrophy. Based on this premise, in this work we investigated the expression of cavernous protein components in liposarcoma (LPS), an adipocytic soft tissue sarcoma that affects adults classified into well-differentiated, undifferentiated, myxoid and pleomorphic histotypes. By performing extensive analysis of microarray data followed by immunohistochemistry on human LPS tumors, we demonstrated that Cav-1, Cav-2 and Cavin-1 always cluster in all histotypes, reaching the highest expression in well-differentiated LPS, the less aggressive than malignant forms composed of tumor cells with morphology similar to mature adipocytes.in vitroexperiments performed with two human LPS cell lines showed that Cav-1, Cav-2 and Cavin-1 protein expression levels were weakly detectable during cell growth, becoming consistently increased during the accumulation of intracellular lipid droplets characterizing adipogenic differentiation. Furthermore, in differentiated LPS cells, the three proteins also co-localize and form molecular aggregates in the plasma membrane, as shown by immunofluorescence and immunoprecipitation analysis. Overall, these data indicate that Cav-1, Cav-2 and Cavin-1 can be considered reliable markers for identifying LPS tumors characterized by consistent adipogenic differentiation.

Journal of Chromatography B, Volumes 1126–1127, 2019, Artigo 121763

Due to increased interest in using excreted sweat for biomarker discovery, data must be generated to support sample collection and handling methods to allow large-scale controlled biomarker discovery studies to be conducted. In this manuscript, twelve amino acids were quantified from exercise-induced sweat excretion maintained at room temperature or a simulated body temperature of 37°C for up to 90 minutes. The data illustrate that there is a large dynamic range between amino acids in sweat. Furthermore, amino acid amounts vary between individuals and between the same individual under different storage conditions, with alanine, arginine, and threonine showing a statistically significant difference between sampling events (p<0.05). Furthermore, the results establish that amino acids are relatively invariant, at both tested storage temperatures, for up to 90 minutes illustrated by <10% (15/156) of amino acid measurements demonstrating greater than 10% change from the zero time value . A non-targeted metabolomics approach was also applied to the dataset to assess global changes in the metabolome. The results show that more than 88% of all data points are within established limits, regardless of temperature condition and ionization mode. Collectively, this study demonstrates that sweat is largely invariant at two distinct temperatures for up to 90 minutes. These results establish that sweat collection and sample handling is possible for up to 90 minutes with minimal changes in metabolite abundances.

Biochemical and Biophysical Research Communications, Volume 466, Issue 3, 2015, pp. 333-338

The skin is responsible for a variety of physiological functions and is critical for wound healing and repair. Therefore, the regenerative capacity of the skin is important. However, the stem cells responsible for maintaining the acral epithelium had not been previously identified. In this study, we identified specific stem cells in the acral epithelium that participate in the long-term maintenance of sweat glands, ducts and interadnexal epidermis and that facilitate the regeneration of these structures after injury. Lgr6-positive cells and Bmi1-positive cells have been found to function as long-term multipotent stem cells that maintain the entire eccrine unit and interadnexal epidermis. However, whereas Lgr6-positive cells cycled rapidly and constantly supplied differentiated cells, Bmi1-positive cells were slow to cycle and occasionally entered the cell cycle under physiological conditions. After irradiation-induced injury, Bmi1-positive cells rapidly proliferated and regenerated injured epithelial tissue. Therefore, Bmi1-positive stem cells served as reservoir stem cells. Lgr5-positive cells cycled rapidly and retained only sweat glands; therefore, we conclude that these cells functioned as lineage-restricted progenitors. Taken together, our data demonstrated the identification of stem cells that maintained the entire acral epithelium and supported the different functions of three cell classes.